They are the leading cause of disability in France and affect one in five people in their lifetime. However, only 2% of the biomedical research budget is devoted to it. Still too often considered shameful, mental illnesses remain the poor relations of medicine. One of the major issues related to these pathologies is the development of better treatments, whether preventive or curative.
For four years, the Marcel Dassault Prize has rewarded researchers who advance the fight against mental disorders. In December 2015, this distinction recognized two researchers for their original and promising work: Dr Laurent Groc, CNRS research director at the Interdisciplinary Institute of Neurosciences (University of Bordeaux), for his research on the causes of psychotic disorders, and Professor Philip Gorwood, head of department at Sainte Anne Hospital and professor at Paris Descartes University, who has worked on the importance of the genes involved in addictive behaviors. Their studies contribute to a better understanding of the molecular, genetic and cellular functioning of these diseases in order to develop new, more effective treatments.
Acting on the immune system to treat schizophrenia
Psychotic disorders are due to interactions between genetic and environmental factors. What about one of the most well-known psychotic disorders, schizophrenia ? Precisely, it is by seeking to know more about the origins of this disease which affects 600,000 people in France (according to theInserm) that Dr. Laurent Groc has demonstrated the existence of a link between schizophrenic disorder and dysfunction of the immune system. Indeed, he realized that schizophrenic patients have a high level of auto-antibodies, molecules made by the body and which destroy the immune system, as if the latter were turning against itself. But to what extent are these autoantibodies linked to schizophrenia? In fact, according to his hypotheses, they modify the functioning of brain circuits and lead to delusions, hallucinationsand psychological disabilities.
In the long term, the objective of the work of Dr. Groc’s team is to detect dysfunctions of the immune system as early as possible, for example by identifying specific markers in the blood of patients. “There is an urgent need to develop innovative therapeutic strategies in the field of mental illnesses such as psychotic disorders. This begins with the search for biological markers in psychotic patients that will allow us to set up, individually, an appropriate treatment.“explains Laurent Groc. These treatments could, for example, consist of blocking the action of auto-antibodies.
Regulating vulnerability genes to treat addictions
Another mental illness in need of treatment: addictive behaviors of all kinds. Again, genetics would be involved in many cases since several studies have shown that there is a vulnerability to addictions of genetic origin. And for Professor Philippe Gorwood, the study of the mechanisms (molecular and cellular) involved in addiction gives hope for the development of treatments. The idea would be to act directly on these genes to limit or cure addictions.
And one of the genes that particularly interests the researcher is the one that makes it possible to produce dopamine, the reward hormone released in large quantities by addictive substances. By reducing the amount of dopamine secreted in the brain of an addict (when he smokes, drinks alcohol or uses drugs), it would be possible to lessen the addiction and therefore facilitate withdrawal.
A convincing example is that of the discovery of a group of vulnerability genes for tobacco addiction. This group is indeed associated in 14% of cases with tobacco dependence and an increased risk of lung cancer. Acting on the expression of these genes would help people who want stop smoking and struggling to achieve it.
At the same time, this genetic track has predictive power: detecting the presence of such genes would make it possible to effectively prevent the risk of dependence even before it occurs. This process will require, according to Philip Gorwood, close collaboration with sociologists and psychologists to find the best way to deliver the message and pass the preventive information to the people concerned. Eventually, this type of genetic screening could be extended to other mental pathologies “for which the vulnerability genes involved will undoubtedly be discovered“, assures Professor Gorwood.
Source: Marcel Dassault Prize press conference, awarded by the Foundation FondaMental and the Dassault group, on September 7, 2015.
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